1. Field of the Invention
The present invention relates to switches and, more specifically, to motion-sensitive switches. The present invention also relates to micro-electromechanical systems (MEMS).
2. Description of the Related Art
An inertial switch is a switch that can change its state, e.g., from open to closed, in response to acceleration and/or deceleration. For example, when the absolute value of acceleration along a particular direction exceeds a certain threshold value, the inertial switch changes its state, which change can then be used to trigger an electrical circuit controlled by the inertial switch. Inertial switches are employed in a wide variety of applications such as automobile airbag deployment systems, vibration alarm systems, detonators for artillery projectiles, and motion-activated light-flashing footwear. Description of several representative prior-art inertial switches can be found, for example, in U.S. Pat. Nos. 6,354,712, 5,955,712, 4,178,492, and 4,012,613, the teachings of all of which are incorporated herein by reference.
A conventional inertial switch is a relatively complex, mechanical device assembled using several separately manufactured components such as screws, pins, balls, springs, and other elements machined with relatively tight tolerance. As such, conventional inertial switches are relatively large (e.g., several centimeters) in size and relatively expensive to manufacture and assemble. In addition, conventional inertial switches are often prone to mechanical failure.